Pyrrosia lingua for Health & Longevity - Quick Reference Sheet
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Pyrrosia lingua for Health & Longevity

Created on 09/13/2026 – Quick Reference based on Evidence Review created using AI4L / Opus 5 – Audit

A dried fern leaf used for two thousand years in East Asian medicine for painful urination, stones and cough, with almost no testing in people. The one human ingestion study found no change in stone-forming urine chemistry. Every benefit rests on animals or test tubes. Cheap and widely available, but sold under a name shared with two other ferns. (Full Review)

Protocol

Standard decoction dose
5–10 g/day
Dried leaf simmered in water; 15–30 g reserved for acute urinary or respiratory complaints. Chinese Pharmacopoeia range 6–12 g.
Best time of day
Morning and early afternoon
A diuretic action taken late produces night-time urination and fragmented sleep.
Single versus split dosing
Split
Short clearance of the marker compounds and the traditional twice-daily decoction both favour dividing the daily amount.
Time to effect
Stone or bone effect
Months
Never demonstrated in people at any timepoint.
Diuretic and urinary symptom effects
Hours to days
Where they occur; reported in traditional practice only.
Reassessment trigger
8–12 weeks
Absence of change removes the rationale for continuing; no delayed-onset effect described.

Benefits

Contraindications
  • Pregnancy and breastfeeding
  • Chronic kidney disease stage 4 or 5 (filtering speed under 30 mL/min/1.73 m²)
  • Heart failure, New York Heart Association Class III–IV (marked limitation or symptoms at rest), on loop diuretics
  • Lithium
  • Cirrhosis, Child-Pugh Class B or C (moderate to severe impairment)
  • Serum sodium under 135 mmol/L or potassium under 3.5 mmol/L at baseline, until corrected
  • Children under 18
    •
Key Interactions
  • Thiazide and loop diuretics (hydrochlorothiazide, chlorthalidone, furosemide)
  • Fluoroquinolone antibiotics (levofloxacin, ciprofloxacin)
  • Narrow-safety-margin drugs cleared by liver enzymes or the efflux pump (warfarin, tacrolimus, digoxin)
  • Over-the-counter non-steroidal anti-inflammatory drugs (ibuprofen, naproxen) and decongestants
  • Potassium supplements and potassium-sparing diuretics (spironolactone)
  • Additive diuretic or urine-alkalinising supplements (dandelion leaf, juniper, horsetail, uva-ursi, potassium citrate)
  • Caffeine, green coffee bean extract and other chlorogenic-acid supplements
  • Sauna, prolonged fasting and endurance training
    •

Risk & Side Effects

  • Speculative: Anxiety and dizziness at large doses; cadmium and heavy-metal carry-over from wild collection; species substitution and large swings in active content; fluid and electrolyte loss from sustained diuresis; interference with drug metabolism and transport; DNA-binding constituents of unknown long-term consequence

Monitoring

Marker Target Why
Serum creatinine and eGFR eGFR ≥ 90 mL/min/1.73 m² Confirms the kidneys can absorb a diuretic action
Serum potassium 4.0–4.5 mmol/L Sustained diuresis drives potassium out
Serum sodium 138–142 mmol/L Catches dilutional drop from high fluid turnover
ALT ≤ 25 U/L (men), ≤ 20 U/L (women) Detects liver strain from an unstandardised botanical
24-hour urine volume > 2.5 L/day The single strongest lever on stone risk, and the herb's claimed action
24-hour urine oxalate < 25 mg/day The exact endpoint the rodent work claims to lower
24-hour urine calcium < 200 mg/day (men), < 150 mg/day (women) Separates dietary and metabolic contributors to stone risk
24-hour urine citrate > 450 mg/day (men), > 550 mg/day (women) Citrate blocks crystal growth and is the main treatable deficit
Whole-blood cadmium < 0.5 µg/L This fern concentrates cadmium, and wild-collected material can carry it

Cadence: Baseline, then 4 weeks, 12 weeks and every 6 months. 24-hour urine repeated at 12 weeks; cadmium at 6 months.

Qualitative Assessment

  • Urinary comfort — burning, urgency and frequency
  • Night-time urination — number of wakings
  • Cough and sputum character
  • Energy and light-headedness on standing
  • Anxiety or restlessness
  • Digestive comfort
Not medical advice. Educational distillation of a single evidence review. Confirm any decision with a qualified clinician, especially in the presence of prescription drugs or chronic conditions.